Originally posted by hoanpham and 28mm/24mm F1.4.
The only 28mm f1.4 is Leica and old Nikon. Why stop here?
And even 24mm and 28mm are noticeably different lenses. It's not without reason that Zeiss' primes include a 21mm, 25mm and a 28mm.
Pentax has a lot of work to do to be a serious option for those that choose a set of high quality primes instead of a few standard zooms. As Zeiss does not intend to get involved in K mount again, and Sigma does neither, Pentax has all the work to do itself.
Leitax K mount to customize Zeiss (Nikon) ZF.2 lenses is a workaround, but not very attractive for those not wanting to tinker with +1000,- euro lenses, and sacrifice all metadata transfer and other communication to the camera.
I currently use a Zeiss 25/2 ZF.2 and 28/2, 35/2 and 50/2 ZK on the (very similar sensor to K1) Sony A7r, and although not everyone will feel the need for four primes in the region very wide-to-normal, it is simply not enough for Pentax to release a single very wide prime. At least not if they want to draw in many new users.
Chris